Portable heater



FIG. 1 is a top perspective view of a portable heater;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right-side view thereof;

FIG. 5 is a left-side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines depict portions of the portable heater that form no part of the claim. The dot dash dot broken lines depict the boundaries of the claim and form no part thereof. 

CLAIM The ornamental design for a portable heater, as shown and described. 